30 Questions
What is the main reason for slowing down enzyme activity at low temperatures?
Decrease in microbial activity
Which temperature range is typically maintained during refrigeration for food preservation?
0 °C to 8 °C
How does freezing help in food preservation?
Inactivating microbes and enzymes
Which of the following is NOT preserved using refrigeration?
Bread
What happens to moisture in food during the freezing process?
It solidifies into ice
Why does packaging food help maintain its color, flavor, and texture during freezing?
To prevent moisture loss
What is the purpose of dehydration in food products?
To inhibit the growth of microorganisms and impart long storage life
How does dehydration differ from drying?
Dehydration can be done by drying, but drying does not always involve dehydration
Why do foods like grapes and figs appear moist even after dehydration?
Because they lack good structure and have high sugar content
How does the surface of food react during quick high-temperature drying?
It becomes dry and rigid before the center dries out
What technology can be used to minimize changes like shrinkage during drying?
Utilizing appropriate technology
How does natural sunlight aid in dehydration?
By quickening evaporation with moderate heat and killing microbes with ultraviolet rays
What is the purpose of water-bath processing in canning?
To heat the food to the temperature of boiling water
What is the main difference between water-bath processing and pressure processing in canning?
Water-bath processing heats food only to the temperature of boiling water while pressure processing heats food hotter than boiling water
Why is pasteurization considered one of public health's most effective food safety interventions?
Because it eliminates pathogens in foods with mild heat treatment
What types of foods are commonly pasteurized?
A variety of foods including dairy products and juices
Who is credited with inventing pasteurization to prevent beer and wine from souring?
Louis Pasteur
Why is pressure processing in canning capable of heating food hotter than boiling water?
Thanks to the pressure canner which increases the boiling point of water
What is the main advantage of direct contact freezing over indirect contact freezing?
Faster freezing process
Which type of freezer is characterized by having food materials separated from the refrigerant by a conducting material?
Indirect Contact Freezing
What is the primary purpose of freeze-drying?
To preserve perishable materials or facilitate transport
What is a common disadvantage of both direct and indirect contact freezers?
Frequent defrosting of plates required
Which type of freezer requires the product to be completely surrounded by the freezing medium?
Direct Contact Freezing
What characteristic distinguishes freeze-drying from direct and indirect contact freezing?
Involves reducing surrounding pressure and adding heat
What is the key difference between pasteurization and sterilization?
Sterilization eliminates all microorganisms, while pasteurization eliminates only pathogenic microorganisms.
Which microorganism is specifically mentioned as being destroyed by sterilization?
Clostridium botulinum
How are packaged products sterilized before marketing according to the text?
By boiling them in water for about 30 minutes
What is the impact of sterilization on heat-sensitive nutrients and proteins?
It significantly reduces their availability
Who is credited with the discovery of pasteurization according to the text?
Louis Pasteur
Which method of sterilization involves the use of high temperatures to destroy all microorganisms?
Dry heat
This quiz covers various methods of treating food with heat like heating, dehydration, canning, pasteurization, and sterilization. It includes information on how dehydration (drying) is used to extract moisture from food products for long-term storage.
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